1. Field of the Invention
The invention relates to a light source module, and more particularly, to a light source module having two layers of light guiding cavities.
2. Description of Related Art
With the advancement of science and technology, bulky cathode ray tube (CRT) displays have gradually fallen into disuse. At present, liquid crystal displays (LCDs), organic light emitting diode (OLED) displays, electro-phoretic displays (EPDs), and plasma displays (PDPs) have little by little become the mainstream flat displays in the next generation.
In a conventional flat display, a direct-type backlight module characterized by 2D local dimming enhances the contrast of the display and economizes the power use; however, the direct-type backlight module requires a rather long light-mixing distance and therefore has a significant thickness. Compared to the direct-type backlight module, an edge-type backlight module has a small thickness, while the edge-type backlight module cannot perform the function of 2D local dimming. Accordingly, the backlight module of the conventional flat display is often required to sacrifice the function of 2D local dimming, suffer from the large thickness, or bear both of the above. Even though the direct-type backlight module equipped with splicing-type light guiding plates may be thinned down, splicing edges between/among the light guiding plates are apt to be shown on the display images due to the different luminance of each splicing-type light guiding plate, i.e., honeycomb or chessboard-like bright and dark zones may be generated in the non-irradiated regions, such that the display quality of the display is deteriorated.